1. Field of the Invention
The present invention relates to a nonvolatile ferroelectric memory device, and more specifically, to a nonvolatile ferroelectric memory device which can access data rapidly in a read operation.
2. Description of the Prior Art
Generally, a ferroelectric random access memory (FeRAM) has the data processing speed as rapidly as a Dynamic Random Access Memory (DRAM), and also retain data even in a power-off state. For this reason, the nonvolatile ferroelectric memory has attracted considerable attention as a next generation memory device.
The FeRAM has a structure similar to the DRAM, and employs ferroelectric as a material for a capacitor to use a high residual polarization characteristic of the FeRAM. The residual polarization characteristic protects data from erasing even when electric field is removed.
Technical features of FeRAM discussed above are disclosed in Korea Patent Application No. 1999-49972 by the inventor of the present invention. Therefore, the configuration of FeRAM and its operation are not described herein.
This conventional nonvolatile ferroelectric memory device stores nonvolatile data in a ferroelectric capacitor, and repeatedly destroys and restores the data stored in the ferroelectric capacitor in a read/write operation of data and in a power-up mode.
Accordingly, the conventional nonvolatile ferroelectric memory device cannot access data rapidly in a read operation due to the repeated destroying and restoring operations. Furthermore, since it cannot overcome the limit of the number of repeated writing operations due to the destroying operation of the ferroelectric capacitor, it falls in reliability and thereby a high-speed nonvolatile ferroelectric memory device cannot be obtained.